Add missing include in <numeric>

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@294393 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/numeric b/include/numeric
index e005808..ff2853e 100644
--- a/include/numeric
+++ b/include/numeric
@@ -65,6 +65,7 @@
 
 #include <__config>
 #include <iterator>
+#include <limits> // for numeric_limits
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header